Winter Storm in Massachusetts, February 15 to 16, 2025

Area Forecast Discussion
National Weather Service Boston/Norton MA
356 PM EST Sat Feb 15 2025

.SYNOPSIS...
A storm system brings a round of wintry precipitation this
evening through Sunday. Precip starts as accumulating snow
before changing to sleet, then rain near the coast, and
freezing rain inland. A cold front brings very strong winds and
cold temperatures Monday. Cold and dry for the middle of next
week, with another chance of snow later in the week with a
potential coastal system.

&&

.NEAR TERM /THROUGH SUNDAY/...

Key Points

* Light to moderate snow moves in from west to east tonight. Snow
  totals range from 2-6 inches south of Rt 2 to 4-8 north of Rt 2.

* Snow turns to sleet and freezing rain later overnight into early
  Sunday morning. Ice accumulation range from .15 to .35 inches west
  of I-495

* Moderate to heavy rain Sunday will likely lead to poor drainage
  and street flooding. Total QPF amounts between 1.5 to 2.5 inches

Potent upper-level shortwave and strong WAA ahead of a 980mb surface
low will bring just about every precip type to the region tonight
through Sunday. Soundings show temperatures below freezing through
the entire column this evening, allowing P-type to start as snow.
Already seeing some light snow flurries show up on radar this
afternoon. Expect snow to increase in aerial coverage and intensity
this evening as better moisture and QPF arrive. Models show decent
850mb FGEN this evening, leading to snow rates of 0.5-1.0 inches per
hour, especially across northern MA. Before the snow ends, expect 4-
8 inches along and north of Route 2, with 2-6 inches south of Route
2 to the south coast. As the strong WAA continues, temperatures
between 3kft to 9kft warm, well above freezing, while remaining
below freezing from the surface to 3kft. This will lead to a period
of light to moderate sleet late overnight, moving north through
early tomorrow morning.

Temperatures at the surface along the coastal plain will quickly
warm above freezing around sunrise tomorrow morning, allowing sleet
to change over to rain with minimal freezing rain concerns. Further
west across the interior, especially in low spots across the high
terrain, cold air will struggle to scour out. This will lead to
possibly several hours of freezing rain, where ice accumulation of
trace to .35 inches is possible.  Any freezing rain combined with
the previously fallen heavy wet snow will lead to snow/ice load
issues on trees and power lines. Isolated power outages are likely
by Sunday afternoon and could become more widespread as strong winds
enter the region with an approaching cold front.

Total QPF amounts will be around 2 inches, with 2.5 to 3 inches near
the south coast, where 100-300 J/kg of MUCAPE could induce some
convective enhancement and isolated rumbles of thunder.  The rain
falling on top of the wet, slushy snow will likely lead to poor
drainage and minor street flooding. MMEFS also shows low probs for
minor river flooding in southern RI.

As for high temperatures on Sunday, a strong temperature gradient
will set up between the coastal Plain and the interior.  Upper 40s
to low 50s are possible in southern RI, CT, and SE MA.  Across the
interior, highs stay in the 30s as cold air struggles to scour out.
A strong cold front moves west to east Sunday night, kicking the
remaining precip offshore and dropping temps quickly into the 20s.
Any standing water that does not evaporate will freeze by Monday
morning, possibly leading to continued slick spots on roadways and
sidewalks.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...

Key Messages:

* Confidence increasing for at least Advisory-level winds Monday

* High temperatures drop into the 20s Monday with the passage of a
  strong cold front

Details...

A strong cold front moves through the region Sunday night. Strong
cold air advection kicks in with it, taking temperatures down from
the 40s into the 20s and low 30s. Subsident flow from the west will
dry the area, but any residual moisture on the ground once the cold
air flows in may quickly freeze, which could lead to possible slick
spots on roads and sidewalks.

Forecast soundings continue to show a well-mixed boundary layer that
mixes up to the 850 mb layer, where winds are approaching 60 to 65
kts in some areas due to a strong jet sitting aloft. If mixing does
occur to this height, there's a good chance for some High Wind
criteria gusts, particularly across the higher elevations
(Berkshires and Worcester Hills). Advisory criteria winds are likely
across the rest of the region. For now, we've opted to keep the High
Wind Watch and will evaluate any warning or advisory decisions in
upcoming updates.

Strong winds and mixing of the cold weather aloft down to the
surface will also bring down temperatures for the region. These
winds will also make it feel even colder than it is, with wind
chills in the single digits into the negatives, especially towards
the interior. Wind chills in the low teens during the day for much
of southern New England are also likely.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...

Key Messages:

* Below normal temperatures, especially early next week. Windy
  conditions bring wind chills as low as -15F Monday night.

* Monitoring potential for a coastal storm Wed-Thu.

Powerful low pressure moves past the Maritimes Monday night into
Tuesday. Expecting it will remain quite gusty during this time, but
not nearly as strong as during the day Monday. A sprawling high
pressure centered near the Dakotas will nose eastward toward
our region during the middle of next week. This should maintain
colder and drier weather through at least Wednesday.

Still have lower than normal confidence in the details towards the
end of next week. Still seeing signs for a potential coastal low
pressure, but the track and timing are uncertain. Latest
climatological anomalies are not particularly strong, which may
be the result of disparate ensemble solutions going into the
mean solution. With cold air anticipated to be in place and an
offshore track, this is looking like mainly snow at this time.
Will continue to monitor this projected storm over this coming
week.

&&

.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
Forecast Confidence Levels:

Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

Rest of Today:

VFR the rest of Today with light winds. Light snow and MVFR CIGS
moves in from west to east this evening between 21z-00z.

Tonight:

Snow may become moderate to heavy overnight with 1/2in to 1.0 in
per hour snow rates. IFR/LIFR CIGS move in with heavier snow.
Snow transitions to light to moderate sleet from 06z-12z from
south to north. A bit of uncertainty on how long sleet lasts
before turning over to rain and freezing rain.

Sunday

For coastal areas, sleet should transition to rain with minimal
freezing rain. Rain will be heavy at times with rumbles of
thunder possible near the south coast. across the interior, but
outside the high terrain, freezing rain fallows the sleet, and
lasts until roughly 15z. In the high terrain. Freezing rain
could last for much of the afternoon. IFR/LIFR CIGS continue
through the afternoon.

Sunday Night.

Cold front sweeps through between 22z-02z, quickly ending any
remaining precip and raining CIGS back to VFR. Very windy behind
the cold front with gusts up to 50 knots.

KBOS TAF...High confidence through 18z Saturday. Moderate after.

KBDL TAF...High confidence through 18z Saturday. Moderate
after.

Outlook /Monday Night through Thursday/...

Monday Night: VFR. Strong winds with local gusts up to 40 kt.

Tuesday: VFR. Windy with gusts up to 35 kt.

Tuesday Night: VFR. Windy with local gusts up to 30 kt.

Wednesday: VFR. Breezy.

Wednesday Night: VFR. Slight chance SN.

Thursday: Mainly VFR, with areas IFR possible. Breezy. Chance
SN.

&&

.MARINE...
Forecaster Confidence Levels:

Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.

Moderate confidence.

The next storm arrives tonight, shifting winds more to the east for
Sunday. Small Craft Advisories have been put in effect for 06z
Sunday through 21z Sunday, when Storm Watches take effect. Sustained
winds Sunday night pick up considerably from the south, reaching up
to 40 knots and gusting up to 50 knots in the marine zones (and
higher gusts possible as you move further out to sea). Winds pick up
in a second burst from the west with the passage of a strong  cold
front over the waters around 06z Monday. Some spots in the southern
waters may see sustained winds up to 45 knots. Wave heights during
this time period may also approach 20 feet in the outer southern
waters. Freezing spray will likely become an issue across all the
marine zones Monday into Tuesday night.

Outlook /Monday Night through Thursday/...

Monday Night: gale force winds with gusts up to 40 kt. Rough
seas up to 15 ft. Freezing spray likely.

Tuesday: Strong winds with gusts up to 40 kt. Rough seas up to
12 ft. Freezing spray likely.

Tuesday Night: Strong winds with gusts up to 30 kt. Rough seas
up to 10 ft. Freezing spray likely.

Wednesday: Low risk for Small Craft Advisory winds with gusts
up to 25 kt. Local rough seas. Freezing spray likely.

Wednesday Night: Winds less than 25 kt. Slight chance of snow.

Thursday: Winds less than 25 kt. Seas locally approaching 5 ft.
Chance of snow. Areas of visibility 1 nm or less.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory until 7 PM EST Sunday for CTZ002>004.
     High Wind Watch from Sunday evening through Monday evening for
     CTZ002>004.
MA...Winter Weather Advisory until 7 PM EST Sunday for MAZ010-011-
     013>021.
     High Wind Watch from Sunday evening through Monday evening for
     MAZ002>024-026.
     Winter Storm Warning until 7 PM EST Sunday for MAZ002>009-012-
     026.
RI...Winter Weather Advisory until 7 PM EST Sunday for RIZ001>007.
     High Wind Watch from Sunday evening through Monday evening for
     RIZ001>008.
MARINE...Storm Watch from Sunday evening through late Monday night for
     ANZ230-236.
     Small Craft Advisory from 1 AM to 4 PM EST Sunday for
     ANZ231>235-237-250-251-254>256.
     Storm Watch from Sunday afternoon through late Monday night
     for ANZ231>235-237-250-251-254>256.

&&

SYNOPSIS...Belk/Hrencecin/KP
NEAR TERM...KP
SHORT TERM...Hrencecin
LONG TERM...Belk
AVIATION...Belk/KP
MARINE...Belk/Hrencecin